Br Dent J 2017; 223: 846–853;

It is easy to understand how cognitive decline can lead to poor oral health, but could the converse also be true? Dementia is a syndrome which causes chronic impairment in cognitive function, hugely impacting the sufferer and those around them. It can affect dental health in many ways: from a reluctance to attend long appointments to forgetfulness when it comes to home care. General dental health professionals see patients (hopefully) over long periods of their life so are in prime position to notice a decline in both their oral and cognitive health.

In this review, Daly and co-authors consider the outcomes of a decade of studies to find a strong association between cognitive decline and poor oral health. They present compelling evidence that dementia can affect oral health in a number of ways. Patients with dementia are less likely to brush twice a day and are more likely to have plaque, caries and poor denture hygiene. This seems logical; patients with dementia may not remember to brush their teeth and may find it difficult to communicate problems with their oral health.

However, unexpectedly, the authors also propose that poor oral health is a risk factor for dementia. Patients with increased plaque and caries were found to be at risk of cognitive decline. Amongst denture wearers, being able to chew properly was linked to a lower risk of dementia. This is a bold claim, suggesting that not looking after your teeth could put you at risk of dementia. The authors are quick to point out that these studies are of variable quality and further well-designed studies are necessary before definitive conclusions can be drawn.

Considering the increasing prevalence of dementia, it is surprising there is little well-designed research into dementia and oral health. This should concern us as this review suggests dental professionals may have a role to play in dementia prevention. The authors rightly suggest declining oral health should be a red-flag to consider causes such as dementia. One thing is certain: these patients and their carers should be shown how to keep a mouth healthy.

In summary, those with dementia are more likely to have poor oral hygiene with a suggestion that this relationship is reciprocal. The authors suggest that further research is desperately needed. Nevertheless this review is an important reminder that, regardless of whether poor oral health increases dementia risk, we must always consider the wider possibilities for declining oral health.

Katherine Kaczmarczyk, Dental Undergraduate, University of Leeds

Learn more about these findings via the 'Oral health is not just about the mouth' animation on the BDJ Youtube channel